The SteriPEN Classic gives you the power to purify water with a single set of batteries, providing you with that extra confidence to know that you'll have access to safe drinking water whenever you're hiking or camping in the wild. Like the Safe Water System Pack (but without the bottle), the Classic with Pre-Filter pack is all that is needed when camping, hiking, backpacking or traveling. Use the 40x40 micron screen Pre-Filter to remove particulates from the water. The Pre-Filter is designed to be stored directly on the wide mouth bottle. Includes a neoprene carry case and User Guide.